1. Field of the Invention
The invention relates to a unique composition of matter of a semiconductive polymeric material, and to humidity sensors and a method of making a humidity sensor from semiconductive coordination polymers, and to "rectifyer-type" electrical elements and to a method of making an electrical "rectifying-type" element from semiconductive coordination polymers.
2. Prior Art
A. Humidity Sensing
Devices capable of the measurement of humidity have numerous industrial, medical, military and agricultural applications. Commonly employed devices include wet and dry bulb thermometers, hair hydrometers, and certain solid state devices.
Among the solid state devices are those described in U.S. Pat. No. 2,613,302 (issued Oct. 7, 1952, to A. M. Gurewitsch, assignor to General Electric Company), comprising a conducting solid film (perhaps a tin oxide) deposited on a non-conducting base; U.S. Pat. No. 2,740,032 (issued Mar. 27, 1956, to G. J. Bouyoucos), comprising a conducting solid embedded in a non-conducting matrix (e.g. resin impregnated plaster); U.S. Pat. No. 3,295,088 (issued Dec. 27, 1966, to W. J. Smith), comprising a conducting solid embedded in a non-conducting matrix (e.g. copolymer of vinylene carbonate and vinyl acetate); U.S. Pat. No. 3,299,387 (issued Jan. 17, 1967, to R. A. Sanford), comprising a non-conducting solid doped with a semiconductor; U.S. Pat. No. 3,848,218 (issued Nov. 12, 1974 to T. Wakabayashi et al), comprising a humidity sensitive film having finely divided conductive particles dispersed in a resin consisting of a reaction product of a chlorine containing polymer and a polyamide resin (note also related U.S. Pat. No. 3,891,958 issued to T. Wakabayashi assigned to Matsushita Electric Industrial Co., Ltd.); U.S. Pat. No. 4,025,892 (issued May 24, 1977 to J. Pompei et al assigned to U.S. Philips Corp.), comprising a layer of semiconductor material (e.g. zinc oxide); and U.S. Pat. No. 4,052,691 (issued Oct. 4, 1977) to K. Nagand et al assigned to Asahi Glass Co., Ltd.), comprising an orthophosphate coating.
Similarly, solid state devices have been produced which sense specific chemical species other than water. For example, U.S. Pat. No. 3,625,756 (issued Dec. 7, 1971, to N. Taguchi) described a method for making gas sensing elements with a semiconductive material (e.g. SnO.sub.2, NiO or Cr.sub.2 O.sub.3); U.S. Pat. No. 3,879,985 (issued Apr. 29, 1975, to C. G. Maslen) describes a specific device using an n-type semiconductor metal oxide (namely zinc oxide doped with 2% platinum) for the detection of hexane and other organic vapors; and U.S. Pat. No. 4,236,307 (issued Dec. 2, 1980, to Colla, et al, assignor to Johnson Controls Inc.) describes a specific device utilizing a semiconductive polymer film (e.g. a pyrolyzed polyaromatic polymer) for the detection of nitrogen dioxide.
The humidity detectors described above consist, generally, of a conducting solid deposited, embedded, or doped onto a non-conducting base or matrix. They are, by their method of preparation, heterogeneous mixtures or dispersions of conductors in or on non-conductors. Further, the response of these devices to broad ranges of humidity is limited and most are adversely affected by atmospheric pollutants.